Method of manufacturing stable pelleted foods



G. T. LANZ July 19, 1960 METHOD OF MANUFACTURING STABLE PELLETED FOODS Filed July 15, 1957 3 Sheets-Sheet 1 July 19, 1960 G. T. LANZ METHOD OF MANUFACTURING STABLE PELLETED FOODS Filed July 15. 1957 5 Sheets-Sheet 2 July 19, 1960 T. LA 2,945,764

METHOD OF MANUFACTURING STABLE PELLETED FOODS Filed July '15, 1957 5 Sheets-Sheet 3 nited States Eaten METHOD OFL'MANUFAQTURINGSTKBBER rnrrmnuroous;

George. QT Lauz,.:Kirkwood-,LMo., .,assignor to ,Ralstou PuriuaCompau-y, St. L6uis,:Mo., a corporation of Mrs- This invention relates. to .a :method ..of. and. apparatus formanufacturing stable: pelleted fo'odsl with additives; and more particularly. to ,animal .feeds having ,a .fat. addif 1 tive, and to the products thereof. Among. the severalobjects of the. invention .may be noted-the provision of. an improved) method and apparatusfor manufacturing gfoodap'e llets having additives providing a substantially higher additive .content than..-,was

of a method of,th cla'ss described. which maybe carried out-by :means offrelatively simple equipment whichis reliable, and convenient to..cont-r.ol.j, Other. obj'ectsgand; features willbe in part apparentand in part pointed? out.

hereinafter.

The invention accordingly" comprises theeleinentsand. combinations of elements, ingredients. andacombin'ations of ingredients, the proportions,thereofifstepsand sequence of. steps, features of construction,compositiohandinar. nipulation, .and arrangementsof parts which Lwillbe. ex'-. emplifi'ed in the structures, products,andmethodshere-. which Qwillb indicate:

inafter described,.and the, scope of ed in the following claims. .7 In the accompanying. drawings,.inpwhich trated,

FigL l isa flowchartillustratinggmy newprocess, said chart 'incorporatingj diagrams .of "apparatus acquired; i.

Fig.' 2 jis an enlargedside elevatioh .of a certain drum, shown in Fig. 1, saidjdrum'bein'galso used inan alterna-. tive .form' of: the process shown.inQFiQjjwhibh is to bereferred to'below; 1

Fig.3 is .a crosstsecti taken on, lines. off

lan -2 H2114 his] a rightendwi'ew of. the, partsof Fig. 2,1lbe-h 5%5 of Fig.,j4;

Fifgi *6 is a process}. v v V 7 is a'flow "chart illustrating anotherwyariation in the process; l v I p Fig'iS. is "a longitudinal section of an, alternative form ofidrttm, useful'forjthetfproce'ss illustrated tangy;

Fig. j110 is a cross. section taknton line fof.

Corresponding refe'rence r characters. indicate corre -t spending; parts throughout.-the-. severalsviews rot-the. drawings.

V several-(of various possible embodimentsof thelinventioh tare illusa vertical fragmentary section taken. on line now; chart illustrating, ayariatioii in ithei Patented July 1 9, 1 9.60

2 While the present inventiomhas" particular application to the production of ipelle'ted' 'feeds hayingfaradditivesr for animals suchas poultryfand cattle (depending upon the size and .composition'ofthe pellets), it.willbe under-' stood that it .is applicable to pelleted human or other. foods,'insofar as the required'additives presentthesamef processing problems. The description'that follows,"=how=;' ever, concerns the addition offa'ts, either'animalbr veg-j etable, to poultry .and cattle feeds, and more particular" lynto the former having a preferred. pellet: diameter of: ,a fraction'of "an;inch such as, for example, /31 inch" or so. I In the case of animal feeds, 'the' diameter may-be on the?" order ofan inch or so. H'eretofore' the addition'of fatstto' pelleted feedslhas'; been'carried out by stirringloose;finelydivided oricom minuted' feed components, usually. jwitlt' some moisture; 1 while at. the same time adding as by spraying, the fat: additive in the form'of a 'liquidor vapor? The resulting 1 material was .then pelleted under. pressure. However: uponthe addition of onlya nominal'amountoffat (for eXample,".l%-4% or. so by weight offeed) the resulting. pellets readily became physically unstable bysofteninggi so that during .transpottationfeither in bulk or ingpack= ages; they tended to disintegrate; thusilo'sing their pelleted; form before being used.i In order;.to reduce such'dis integration, the amount-of fat addedwas minimized. This of coursereduced the energy 'contentpf-theufeed that might otherwise. have'been obtained by adding morefatt' According'zto the present invention, it"is possible to produce a pellet having a much higher percentage-of" fat content (for example; 10%""or morebyiweighty with'-' out disintegration occurring ,during shipment and, before. feeding. Thus th'epelletsfproduced according toj'my in-fl ventionare harder and have more.physical'stability and i a much higherienergy content, besides .being i'n'a more desirable conditionnforingestion. 1

Referring now more .particula'rly'to Fig;;1,there is; shown atinumerall a supplybin for; the comminuted' food material or meal to be pelleted. For'example, in the. caseiof a poultry feed. thismight be ground 'corn,"oats;..

. alfalfa mealgqwheat, barley or th'elike, with suitable;

additives such "as vitamin andtantibiotic supplements,"

trace chemicals-or th'e'likeg; In thel-caseioflanimal feed zthis may be any. suitabl'eigroundkfoiider'wimsupplements:i Thislist'is to be takenas suggestive andnotes limiting:

Meals, such above.suggestedfflowslfrornithe"bin 7 pelletingg this jaddition .of steam'i'mayjbe unnecessaryz' The pelletmill ii'is conventionalfland' under pressure;

' mph e ere di g pm the pe sieh'a teti if produces, for example, short cylindric pellets in the caseoffp oultry feed, aboutfi/ i inch in diameter anditi' inch i tmc or? Q e f' e i nsl; size j ar c nfihl milf3 I During the}pelltingprocess in the'pellet millS, material" is' squeezed .throughfldies'. "which substantial yi; compressiand' heat" it, the. compression-resulting in for-mm tion of .vermicular 'strarrds whichI-are: automatically cut to' pelletxlengtl rfi The pelleitspmay belejected' frt'un th'emill ata temperatureon {the order; for. example; of".1 80- F3 At this.time they areimconditionto hold their shape during'furtherrhandling in thepIpCeSsJQ I Fromgthe pellet milhfithe .pell'e'ts pass" to" a tempering pellet drier[7 in, which *they ,are subjected to ,a blast ,of,

. war-main. Thedrierkmayb ofany-eonventioiial type,-:

a .multipass. typebeing shownw Thisfresults,inhholdingt.

the. pellets at atemp erature of,.ffoi-II.e)rample; %1201.

E, which is a temperature above that of certaipghot liquid fat to be applied to the pellets and to be referred to below. This temperature also results in drying the pellets.

.From the pellet drier the pellets pass to a two-way control valve or gate 9. The gate 9 may be adjusted to direct the pellets to a conventional shaking screen 11, either directly through a by-pass 15, or via a set of cracking rolls 13. If they move over the by-pass 15, they retain their pelleted form, whereas if they pass through the cracking rolls they are cracked into fractional pelleted form. In either event they are herein referred to as pellets. The screen is of suitable mesh to eliminate fines and undesirably small particles.

The screened pellets pass through a control gate 17 in a passage 51 and through a stationary head 21 of a downwardly sloping rotating tumbler drum assembly 19. The lower end 23 of the drum assembly is open and interiorly it contains lifting. flights 25, so that the pellets are rolled over and over as they pass down from the head 21 to the outlet end 23. As shown in Fig. 3, there will be a tendency for the main mass 27 of the pellets to aggregate on one side of the drum assembly at the head 21. At this aggregation area of the head 21 there is provided an air inlet 29 with which is connected an air duct 31 from a fan 33. In the duct 31 are suitable heating means 35 such as a set of steam coils adapted to bring the air temperature up, for example, in the range of 200-300 F., with 250 F. preferred in the case of the use of animal fat. This hot air becomes introduced into the pellet aggregate 27 and circulates through it, tending to flash off any moisture, thus drying the pellets, particularly on their surfaces. It also maintains the pellet temperature at a value higher than the melting temperature of fat to be applied, as will appear below.

At numeral 37 is shown a supply pipe, passing through the head 21 and extending along the inside of the drum assembly in the open area not occupied by the aggregate 27. This open area is shown at 39. The pipe 37 is provided with an inlet valve 41 for controlling the flow of hot liquid fat through the pipe 37. For example, this fat may be on the order of 110l30 F. temperature, with 120 F. preferred in the case of the use of animal fat. The pipe contains axially spaced spray nozzles 43 for spraying the hot fat across the drum assembly. Thus it coats evenly the surfaces of the flash-dried tumbling pellets passing through the drum assembly 19. The fat is rapidly absorbed into these dry surfaces and enters the interstitial spaces between the interior constituentparticles of the pellets.

From the open lower end 23 of the drum assembly 19, the fat-impregnated particles pass into a bin 45 for subsequent passage to suitable packaging means (not shown) such as bag-filling machinery. Ordinarily they are left to cool naturally in the bin. However, if desired, they may be artificially cooled before reaching the bin.

In Fig. 6 is shown a second method and apparatus wherein like numerals designate like parts. In this case the pellets emerging from the pellet mill 3 pass first to an oscillating screen 47 'of the type known as a scalper, which also eliminates fines and excessively' small particles.

control gate or valve 49 In the drum assembly they are sprayed with the hot fat, as already described in connection with Fig. 1. The drum assemblyv has connected therewith the air supply and hot-fat spraying elements already described and indicated by similar reference characters in Fig.6. From the lower end 23 of the drum assembly (in Fig. 6) the fat-treated pellets pass to and throughthe drier 7 and thence through gate 9 and either through cracking rolls 13 or by-pass to the screen 11. From the screen 11 the treated pellets pass to the bin 45 and then to the packers, as above dc scribed. 3

Then the pellets pass into the drum assembly. 19 via its stationary head 21. This is done through a.

The method according to Fig. 6 may be characterized as a hot method, in that the heat in the pellets due to treatment in the pellet mill is not tempered prior to the time that they reach the drum assembly 19, the tempering step being reserved for application to the pellets after they emerge from this drum assembly 19.

lhe temperatures above given are suggestive and are not to be taken as limiting. They apply to the use of animal fat such as tallow, grease or fish oil for spray application of the pellets. It will be understood that vegetable fats may also be employed, such as soybean oil, cottonseed oil, or palm kernel oil or the like, and that .somewhat different preferred heating temperatures may be required for the vegetable oils.

Since an important element of the invention is the application of the hot-fat spray to the pellet surfaces while themselves hot and after they have been pressed into form and flash-dried (rather than as formerly to their constituent meal before pelleting), and since the drum assembly 19 accomplishes the flash drying and fat application, further details of the drum assembly are disclosed as follows:

The drum assembly 19 is constituted by an outside cylinder or drum 53 which has a rotary running fit within a stationary flange 55 attached to the head 21, as shown in Fig. 5. At this point a cotton web sealing ring 57 is held in position on the end of cylinder53 by means of a strap 59, a lip 61 extending over the flange 55 and forming a running seal. The head 21 has a second stationary, inwardly spaced flange 56.

The drum 53 is supported upon idling rollers 63, carried upon a sloping framework 65. Slope may be adjusted by means of the adjustment rod 67. Pivoting of the upper portion of the framework 65 then occurs at pivot 69 with respect to the lower portion thereof. A sprocket 71 is carried on the drum 53, the sides of which are engaged by rollers 73 to prevent axial movement of the drum 53. A chain 75 engages the sprocket 71 and a second sprocket 77 on the shaft of a driving motor 79, the latter being carried on a bracket 81 slung from the underside of the upper portion of the framework 65. Thus the motor 79 rotates the drum 53 through the sprocket and chain drive 71, 75, 77. At its lower end, the drum is partially enclosed by an inwardly directed annular flange 83, from which extends the open outlet 23 in the form of a snout. A clean-out gate 85 is provided in the flange 83.

Welded to the inside of the drum 53 are a series of annular angle-iron hoops 87, to which are welded the elongate imbricated flanges 89 of elongate baffle plates 91. Each of the baffle plates 91, including its portion 89, extends throughout most of the length of the drum 53, i.e.,

' from flange 83 to flange 56. Each bafiie plate 91 carries lugs 93 at spaced intervals on its outer margin. Thus the margin of each bafile plate is prevented by its lugs from engaging the margin of the adjacent baflle plate, so that any air that may be introduced axially under pressure between the baflie plates may escape in a peripheral direction to enter the interstices within the pellet aggregate where the latter rests upon the bafile plates 91 (see Fig. 3 Every fourth baffle plate has welded thereto one of of the axiallyextending lifts 25. These lifts during drum rotation are covered by the aggregate 27 and tend successively to expose the pellets to the spray issuing from the nozzles 43.

An examination of Fig. 4 will indicate that the hot air inlet 29 is in such a position on the stationary head 21 as to introduce air axially into the spaces between the baflle plates 91. These spaces are numbered 95 (Figs. 3, 4 and 5). The rotation of the drum 53 (see the outside darts D in'Figs. 3 and 4) is such, relative to the direction of imbrication of bafile plates 91, that the pellets do not tend to be introduced from aggregate 27 into the spaces 95, each baflfle plate 91 shielding the other against such, action. The few pellets that may accidentally enter this 56onto the battle plates 91,, finding theirl wayjdown along, the drum on the inside marginsof the battles] The lifting flights 25 tend toaggregate them onone side ,oithedrum, as shown at 27, while .atthe ,same time, moving ,themnfor successiveexposure to the .oihspray from the, nozzles43:

by raining the pellets dow'npas't the nozzles, Hot air enteringthe inlet 29 isintroducedinto thespac'es95 between the baffle plates 91 in .the region ,withirithedrirm where these bafile platesare. underthe pellet aggregate 27., Since the spaces 95.are enclosedat} the lowerend ofthe drum by the annular ,fiange. 83., and at the ,Otherend of the drum by the stationaryihead 21,.this air canescape from the spaces 95 primarily only by. passingthrough the. mass aggregate 27,; whichhas .the effect of flash-drying the surfaces of the. pellets. and ,some portions ofsthem under their surfaces. Then when they are eompletelyexw posed to the hot-fat vsprayby ,action ofwtheilifts .25., the; surfaces arein a hot dry absorbent conditionrapidly to attract and toabsorb .a,substantia;l :amountyof hot fate Since in the flash-drying.process the pellets are given a substantially hardened structure which the, absorbed {fat does not tend to breakdown, the; pellets emerging from,

the lower end 23. are otthe, improved nature desired; that is to say; they; have an absorbed quantity of fat whichis very substantially greater, withoutweakening the pellets, than was-heretofore possible ,to incorporate therein by the, old process ofapplying thezfat.beforepelletizing Upon cooling, the. fatsolidifies and most, if not, all, disintegrate ing action isavoided;

Fig; 7 illustrates a third embodiment .of the invention, incorporating a modification in part of the process il l, lust-rated in Fig. .1. In ,this", embodiment, the ,rnate'rials are first subjectedtov theractionseofnthe devices l,,3,f. 7, 9, 11 and 1-3 or 15; asdescribed .inconnection 'with- Fig; 1; Of-these mernber,s,.the.screendl is repeated in Fig.1 7.; No control-agate such asll isemployed at the;

outlet of the. screen- 11; (Eig;.;.-.,7) Instead; the pellets, which are still sufficiently warm trom the tempering de vice 7 preferably;to be,above the..liquidiattemperature, pass directly fromthe screen 1 1 to a bin' 97." This bin may be small and employed primarily to regulate surges, or it may be large..enough ,to provide some; storage capacity. Then the material, whlllef still sufficiently warm and dry, passeslover, .:a,,b.e lt feeder -.,99 ;1and downward through a vnosepiece. ll,wso con,structedthat its gtrajectory is in the form ofa more or less fl-at relatively thin curwin-fall p e rablv pfl mvw dth it-t in ess- Th e rm vbe of. the .cqnv a qa lg lledswimetric type which transmits a signal showing at all times the rate at which material is passing over the belt. Being known, further description is unnecessary.

The criterion for the curtain form is that it shall, during free fall of the pelleted material through a containing box 105 around the curtain, expose most if not all of the pellets (whole or cracked) to a spray or mist 107 of the liquid fatty material such as above described. This spray or mist is obtained by supplying the hot liquid fat under pressure over a line 109 to opposed batteries 111'of spray nozzles on opposite sides of the curtain. The supply may be controlled from valve 110 in accordance with the amount of pelleted material passing over the belt conveyor 99. The nozzles are so placed that all available curtain area on both of its sides is covered by the spray as the pellets tumble past it. Inspection doors (not shown) may be employed on the box 105.

The fat-impregnated warm pellets then fall out of the open bottom of the box 105 into a connected hopper 113, so constructed that its sides are steep enough to prevent build-up of the material therein. From the lower end 115 of the hopper 113, the material flows r air is introduce as oatmeala a m-w r 19,'; contains; within it no spraying elements but only X heating and tumbling means; I

The drum *1'17iis illustratedin Figs, 8 -10; It -is*constituted by spaced outer and inner cylinders119' and.

121,,joined by-a lower annular head 1 23, --le av.ing a centrallower outlet from the inner cylinder 121., The cylinders 1 19, and 'lllf are' held in spaced" relationship by spaced longitudinal ribs 120, which' extendfshortor the head 123 so as toleave a lower annular space shown at 131;; These;ribs--120*for m'-flues-between them.- At theupper end ofthe'drmn is an inner"head-127, at-

tachedto the-inner drum 121 and rotatable therewithb Outside is a stationary head 129 held in placeby supports 130. Head 129h as a running 'outsidefseal 131 with the outer cylinder 1192-"- The lower hopper end llsextendsi through centralopenings in the head-s -lz7 and l29, so

as to deliver m-aterial into the inside of} the cylinder 121 iasboth' 'cylinders119 and-121 rotate. This m ateriahi as the drum rotates-,' is subject tothe stirring action of axially arranged paddles-133; which= are carried upon; supports 135' welded to the inside of the inner drum 1121. I

The drum is rotated by a chain drive:137 tromarnotor 139 suspended on a frame 1 41. The frame rollers 14 3fwhich rotatably support the drum; The: drum is prevented from' sliding downward by means such as de-:.

scribed in the case of drum' l9, but not detailed in Figsl 8 and 10. Ari adjustable -supportmgframework for the.

drum and motorisindeXed i 'At; numeral; '147;is-'shown:a hot air inlet and at 149'.

is'shoWn-a warm air 'outleto These. are on opposite? sides:

of the drum and connect with thec-spacexbetwe'en cylin-;

ders--1 19' and 121: through the. stationary head 1291* Hot of the-drum between-cylinders 1'19. -and:12:1' andyafter: passing through-theannulus 131," returns between the cylinders to the warm air outlet.= .149.: Thus'therpellet:

coolingito'; -a"zpacltagingbstationz 'Ihisdhirdform of the.

invention has, theapa icular advantage that. there ,is less. lag ppenetarting and ending a production: run in-gettingall of-thenpellet. outputaimpregnated, since this method more. rapidly: exposesgall pelletslto thefat spray.

It is to be noted that in all forms of the invention. the tempering unit 7 functions as a drier for driving off moisture Tlie drying act ion, jamong other things above mentioned,jservestoprepare the pelletsfo r' better crackin'g action by rollers "13, in' all forms of the invention The following are exemplary of the improvements ass-- complished by means of the invention. Poultry pellets have been produced which, according to standard tests, are 300% harder for a 10% by Weight fat content than pellets made by former processes having only a 4% or less fat content. 'Heretofore, pellets containing more than about 3% of fat by weight have been rendered practically uselss, or at least much'inferior as pellets, by disintegration during shipment. While I do not wish to be restricted by any explanations for this result, I believe it is due to the fact that when fat was formerly applied to the comrninuted unpelleted and cool granular material it preliminarily coated the particles to form barriers against \good coalescence during pelleting, with resultant weakening of the pellets after pelleting. The more fat was added, the more they were weakened. This placed a low limit upon the amount of energy-producing fat additive that could be introduced without causing the pellets to disintegrate during storage and transportation. On the other hand, according to my process,

the feed particles are pelleted in the absence of any fat barriers, the fat being applied after coalescence by presintor the inlet'wand traverses the length sure and flash-drying and heating has occurred. The free flowing cfat then readily enters a strong structure by absorption into the interstices between the coalesced dried particles and does not interfere with the dried pressureproduced bonds between the constituent particles of the respective pellets. The application of hot fat to the hot dry particles is important, inasmuch as this brings into operation an attraction of hot fat into the pellets by absorption without entailing later disintegration after the fat has cooled.

In the above, it will be understood that the members 1 1 ('Fig. 1) and 47 (Fig. 6) both act as riddles to eliminate small broken pieces and fines from the pellets or acceptably sized parts thereof.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

' As various changes could be made in the above methods, constructions and products without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall beinterpreted as illustrative and not in a limiting sense.

7 I claim:

' 1. The process of manufacturing feed for animals, poultry and the like, comprising pelleting comminuted feed under pressure from a finely divided state into pellets, heating the pellets to drive off a substantial amount of any contained moisture to produce a relatively low moisture content in the material of the pellets at least at and near their surfaces, and spraying hot liquid fat on the pellets while hot.

2. The process of manufacturing feed for animals, poultry and the like, comprising pelleting comminuted feed under pressure from a finely divided state into pellets, simultaneously heating and tumbling the pellets to drive off a substantial amount of any contained moisture to produce a relatively low moisture content in the material of the pellets at least at and near their surfaces, and spraying liquid fat on the pellets while they are tumbling and hot. I

3. The process of manufacturing'affeed product for animals, poultry and the like, comprising pelleting under pressure comminuted moisture-containing feed from a finely divided state into hot pellets, tempering, screening, and tumbling the pellets in the presence of a current of hot air adapted to dry them at least at their surfaces, and spraying hot fatty material thereon during the hot tumbling operation.-

4. The process of manufacturing a feed product for animals, poultry and the like as set forth in claim 3, including a cracking step between said tempering and screening steps.

5. The process of manufacturing a feed product for animals,-poultry and the like, comprising pelleting under pressure comminuted moisture containing feed from a finely divided state into hot pellets, scalping said pellets, tumbling the pellets in the presence of a current of hot air adaptedto dry them at least at their surfaces, spraying-hot fatty material thereon during the hot tumbling operation, tempering the pellets and screening them.

,16. The process of manufacturing a feed product for animals, poultry and the like as set forth in claim 5, including a cracking step between said tempering and screening steps.

7. Theprocess of manufacturing a feed product for animals, poultry and the like, comprising pressure-pelleting a finely divided moisture-containing mass of feed meal, tumbling and simultaneously drying the pellets in a current of hot air adapted to drive off at least surface moisture and to heat'the pellets, spraying the pellets with hot-liquid fat in their hot condition while being tumbled, and tempering the resulting fat-containing pellets.

8. The process of manufacturing a feed for animals, poultry and the like, comprising pelleting comminuted feed under pressure, driving off from the resulting pellets asubstantial amount of moisture by warming the pellets to a temperature higher than that of hot liquid fatty material to be applied thereto, and spraying said pellets while warm with a hot liquid fatty material adapted to be absorbed as a liquid into the pellets.

.-9. The process of manufacturing a feed for animals, poultry and the like, comprising pelleting moist comminuted -feed under pressure to form pellets, raising the temperature of the pellets to a degree higher than that of hot liquid fatty material to be applied thereto to drive oil? a subsantial amount of any contained moisture, and spraying said pellets while at said temperature with a hot liquid fatty material adapted to be absorbed into the dry pellets. 7 v

a 10. The process ofmanufacturing a food product comprising pelleting comminuted food under pressure from a finely divided state into pellets, heating the pellets, subjecting the pellets while hot to impregnation in a substantially free fall through a mist of hot liquid fatty material, and agitating the pellets after said fall in a hot condition.

12,806,788 Leker Sept; 17, '1957 

1. THE PROCESS OF MANUFACTURING FEED FOR ANIMALS, POULTRY AND THE LIKE, COMPRISING PELLETING COMMINUTED FEED UNDER PRESSURE FROM A FINELY DIVIDED STATE INTO PELLETS, HEATING THE PELLETS TO DRIVE OFF A SUBSTANTIAL AMOUNT OF ANY CONTAINED MOISTURE TO PRODUCE A RELATIVELY LOW MOISTURE CONTENT IN THE MATERIAL OF THE PELLETS AT LEAST AT AND NEAR THEIR SURFACES, AND SPRAYING HOT LIQUID FAT ON THE PELLETS WHILE HOT. 